Flashcards in Amphibians Deck (19):
What 3 groups make up lissamphibia?
1. Anura = the frogs
2. Caudata = the salamanders and newts
3. The gymnophiona = the caecilians
What is the Batrachia Hypothesis?
The the anurans and caudates form a clade sistergroup to the gymnophionans.
Where is the greatest diversity of the anurans?
Where is the greatest diversity of the caudates?
The northern hemisphere, they are 'holarctic'.
Where is the greatest diversity of the caecilians?
The Southern Hemisphere.
Eustenopteron and Pandrichthyes were early tetrapods. They still had fishy fins and gill arches. What indicated they were evolving towards terrestriality? Give 2 reasons.
Had lost the operculum.
Had a longer snout = less after flow over the gills and changes in feeding methods.
What features of Tiktaalik indicated terrestriality?
Strong pectoral and pelvic girdles.
Strong zygopophyses to prevent flexion/torsion.
A more distinct neck region.
What is the urostyle?
Fused caudal vertebrae in anurans for jumping muscle attachment.
What adaptations do anurans have to allow them to climb surfaces?
Adhesive toe pads (and sometimes some on the belly) that secrete mucus.
How do caudates move?
Undulate in water and a sprawling gait on land.
How do gymnophionans move?
They are completely limbless and live a fossorial lifestyle. They have 'internal concertina muscles' visible in the dermal annuli for lateral undulation.
Do gymnophionans have eyes?
No as they are fossorial and have retractable sensory tentacles instead.
How do amphibians respire?
Cutaneous and pulmonary respiration, however the proportion varies between species.
Amphibians have glandular skin, what does this mean?
It must be kept wet at all times by mucus.
Lungs are present in amphibian larvae. Are these used to breathe?
No - only the gills are used for breathing. The lunge become functional after metamorphosis.
Which types of amphibian species rely MORE on pulmonary respiration?
Those that are more active or have higher body temperatures.
Bottom-dwelling amphibians do not need lungs. Why?
Lungs are positively buoyant.
Amphibian eyes have 2 major features. What are they?
Thickened cornea = focuses both on land.
Moveable lens = helps to focus eye in water.